Apparatus and methods for contactless electrophysiology studies

ABSTRACT

An electrophysiology catheter includes an elongate catheter body having an elastically-deformable distal region predisposed to assume a spiral shape and a first plurality of electrodes disposed thereon. Each of the first plurality of electrodes includes an electrically active region limited to the inner surface of the spiral shape for use in non-contact electrophysiology studies. A second plurality of electrodes may also be disposed on the distal region interspersed (e.g., alternating) with the first plurality of electrodes, with each of the second plurality of electrodes having an electrically active region extending into the outer surface of the spiral shape for use in contact electrophysiology studies. The distal region may be deformed into a straight configuration for insertion into and navigation through the patient&#39;s vasculature, for example via use of a tubular introducer. As the distal region deploys beyond the distal end of the introducer, it resumes the spiral shape.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. application Ser. No. 12/131,750,filed 2 Jun. 2008, which is a division of U.S. application Ser. No.11/734,191, filed 11 Apr. 2007, now abandoned, which is a division ofU.S. application Ser. No. 09/547,945, filed 12 Apr. 2000, now abandoned,which is a division of U.S. application Ser. No. 09/005,105, filed 9Jan. 1998, now abandoned, which is a continuation in part of U.S.application Ser. No. 08/387,832, filed 26 May 2005, now U.S. Pat. No.6,240,307, which is a national stage entry of PCT/US93/09015, filed 23Sep. 1993, which is a continuation in part of U.S. application Ser. No.07/950,448, filed 23 Sep. 1992, now U.S. Pat. No. 5,297,549, which is acontinuation in part of U.S. application Ser. No. 07/949,690, filed 23Sep. 1992, now U.S. Pat. No. 5,311,866. Each of the foregoing is herebyexpressly incorporated by reference as though fully set forth herein.

BACKGROUND OF THE INVENTION

a. Field of the Invention

The instant invention relates to catheters that are used in the humanbody. In particular, the instant invention relates to anelectrophysiology catheter for use in electrophysiology studies,including, without limitation, electrophysiology studies where sensingelectrodes are in contact with the tissue being measured andelectrophysiology studies where sensing electrodes are not in contactwith the tissue being measured. The present invention also relates tomethods of manufacturing and using such a catheter.

b. Background Art

Catheters are used for an ever-growing number of procedures. Forexample, catheters are used for diagnostic, therapeutic, and ablativeprocedures, to name just a few examples. Typically, the catheter ismanipulated through the patient's vasculature and to the intended site,for example a site within the patient's heart.

A typical electrophysiology catheter includes an elongate shaft and oneor more electrodes on the distal end of the shaft. The electrodes may beused for ablation, diagnosis, or the like. Oftentimes, these electrodesare ring electrodes that extend about the entire circumference of thecatheter shaft. Thus, when the catheter is introduced into the patient'sbody, there is the potential for the electrodes to come into contactwith tissue surfaces.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to provide an electrophysiologycatheter including at least some electrodes that do not come into directcontact with cardiac tissue surfaces during an electrophysiology study.

It is another object of the present invention to provide a kit usable inelectrophysiology studies where at least some of the sensing electrodesdo not come into contact with tissue surfaces during theelectrophysiology studies.

Disclosed herein is an electrophysiology catheter including: an elongatecatheter body having an elastically-deformable distal region predisposedto assume a spiral shape having an inner surface and an outer surfacewhen in a relaxed condition; and a first plurality of electrodesdisposed on the distal region, each of the first plurality of electrodeshaving an electrically active region limited to the inner surface of thespiral shape. The electrophysiology catheter optionally also includes asecond plurality of electrodes disposed on the distal region, each ofthe second plurality of electrodes having an electrically active regionextending into the outer surface of the spiral shape. The firstplurality of electrodes and the second plurality of electrodes mayalternate (e.g., every other electrode is an electrode from the firstplurality of electrodes and vice versa).

A shape memory material may extend through the distal region of thecatheter body to predispose the distal region into the spiral shape.Suitable shape memory materials include shape memory metal wires andshape memory polymers. Where a shape memory metal wire is used, at leasta portion of the shape memory metal wire may be encased in a polymerictube.

In alternative embodiments, a spring element may extend through thedistal region of the catheter body to predispose the distal region intothe spiral shape. In still other alternative embodiments, the distalregion of the catheter body may include a polymeric material that isthermoset into the spiral shape.

At least some of the first and/or second pluralities of electrodes maybe ring electrodes. With respect to the first plurality of electrodes,portions of the ring electrodes on the outer surface of the spiral shapemay be covered by an electrically insulating material so as to limit theelectrically active region thereof to the inner surface of the spiralshape. Alternatively, at least some of the first plurality of electrodesmay extend about a fraction of the inner surface of the spiral shape(e.g., the electrode itself is limited to the inner surface of thespiral shape).

The spiral shape of the distal region of the catheter body has a centralaxis, while the elongate catheter has a longitudinal axis. It isdesirable for the central axis of the spiral shape to extendcontinuously from the longitudinal axis of the elongate catheter. Thatis, it is desirable for the distal region of the catheter body to besubstantially centered on the remainder of the catheter body.

In another aspect, a kit for conducting electrophysiology studiesincludes a guidewire and/or a tubular introducer having an elongateintroducer body having a distal end, a proximal end, and a lumenextending from the proximal end to the distal end; and anelectrophysiology catheter. The electrophysiology catheter, in turn,includes an elongate catheter body that is deployable through the lumenof the introducer and/or introduceable over the guidewire. The distalregion of the catheter body is elastically deformable and predisposed toassume a spiral shape having an inner surface and an outer surface whenin a relaxed state unconstrained by either the introducer or theguidewire. The distal region of the catheter body also includes aplurality of electrically active regions, wherein each of the pluralityof electrically active regions is limited to the inner surface of thespiral shape. The tubular introducer optionally includes a steeringmechanism operable to deflect the distal end of the elongate introducerbody in at least one degree of freedom.

Also disclosed herein is a method of conducting an electrophysiologicalstudy that includes the following steps: providing an electrophysiologycatheter having an elastically deformable distal region predisposed toassume a spiral shape having a central axis when in a relaxed state andincluding a plurality of electrically active regions facing the centralaxis of the spiral shape; introducing the electrophysiology catheterinto a patient; and gathering electrophysiological data using theplurality of electrically active regions without bringing theelectrically active regions into contact with tissue.

Typically, the step of introducing the electrophysiology catheter into apatient comprises introducing the electrophysiology catheter into thepatient via the patient's vasculature. It may also include: insertingthe electrophysiology catheter into a tubular introducer, therebycausing the distal region of the electrophysiology catheter to assume acollapsed shape conforming to the introducer; introducing the introducerwith the electrophysiology catheter inserted therein into the patient;navigating the introducer with the electrophysiology catheter insertedtherein to a first location of interest; and deploying the distal regionof the electrophysiology catheter from the tubular introducer at thefirst location of interest, thereby causing the distal region of theelectrophysiology catheter to resume the spiral shape.

The method may optionally include the following steps: retracting thedistal region of the electrophysiology catheter into the tubularintroducer, thereby causing the distal region of the electrophysiologycatheter to resume the collapsed shape; navigating the introducer withthe electrophysiology catheter inserted therein to an additionallocation of interest; and deploying the distal region of theelectrophysiology catheter from the tubular introducer at the additionallocation of interest, thereby causing the distal region of theelectrophysiology catheter to resume the spiral shape.

In yet another aspect, a method of manufacturing an electrophysiologycatheter includes the steps of: forming an elongate catheter body havingan elastically deformable distal region; predisposing the distal regionof the elongate catheter body to assume a spiral shape when in a relaxedstate; and mounting a plurality of electrodes to the distal region ofthe elongate catheter body, each of the plurality of electrodes havingan electrically active region limited to an inner surface of the spiralshape. The step of predisposing the distal region of the elongatecatheter body to assume a spiral shape when in a relaxed state mayinclude placing a shape memory metal wire having a memory shapecorresponding to the spiral shape into the distal region of the elongatecatheter body. Alternatively, the step of predisposing the distal regionof the elongate catheter body to assume a spiral shape when in a relaxedstate may include placing a spring temper wire biased into the spiralshape into the distal region of the elongate catheter body.

Devices and methods according to the present invention advantageouslypermit the conduct of electrophysiology studies, such as the generationof heart chamber maps, without bringing sensing electrodes into contactwith a tissue surface.

Another advantage of devices and methods according to the presentinvention is enhanced compatibility with localization systems, such asthe EnSite NavX™ navigation and visualization system of St. JudeMedical, Atrial Fibrillation Division, Inc.

The foregoing and other aspects, features, details, utilities, andadvantages of the present invention will be apparent from reading thefollowing description and claims, and from reviewing the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a representative electrophysiology catheterhaving a spiral-shaped distal region and interior-facing electricallyactive regions. Also visible in FIG. 1 is an exemplary introducercatheter.

FIG. 2 is an isometric view of the electrophysiology catheter andintroducer catheter of FIG. 1.

FIG. 3 is a partial cutaway side view of the electrophysiology catheterdepicted in FIG. 1.

FIG. 4 is a side view of a representative shaping wire that can be usedto predispose an electrophysiology catheter according to the presentinvention to assume a desired spiral shape.

FIG. 5 is an isometric view of the representative shaping wire depictedin FIG. 4.

FIG. 6 is an axial cross section of the distal region of anelectrophysiology catheter according to some embodiments of the presentinvention, including a shaping wire embedded in the catheter wall.

FIG. 7 is an axial cross section of the distal region of anelectrophysiology catheter according to other embodiments of the presentinvention, including a shaping wire encased in a polymeric tube.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described with reference to anelectrophysiology catheter utilized in cardiac electrophysiologystudies. It should be understood, however, that the present teachingsmay be applied to good advantage in other contexts as well.

Referring now to the figures, FIGS. 1 and 2 depict an electrophysiology(“EP”) catheter 10 according to a first aspect of the present invention.FIG. 1 is a side view of EP catheter 10, while FIG. 2 is a perspectiveview of EP catheter 10.

EP catheter 10 generally includes an elongate catheter body 12 having adistal region 14. EP catheter 10 will typically be made of abiocompatible polymeric material, such as polytetrafluoroethylene (PTFE)tubing (e.g., TEFLON® brand tubing). Of course, other polymericmaterials, such as fluorinated ethylene-propylene copolymer (FEP),perfluoroalkoxyethylene (PFA), poly(vinylidene fluoride),poly(ethylene-co-tetrafluoroethylene), and other fluoropolymers, may beutilized. Additional suitable materials for catheter body 12 include,without limitation, polyamide-based thermoplastic elastomers (namelypoly(ether-block-amide), such as PEBAX®), polyester-based thermoplasticelastomers (e.g., HYTREL®)., thermoplastic polyurethanes (e.g.,PELLETHANE®, ESTANE®), ionic thermoplastic elastomers, functionalizedthermoplastic olefins, and any combinations thereof. In general,suitable materials for EP catheter 10 may also be selected from variousthermoplastics, including, without limitation, polyamides,polyurethanes, polyesters, functionalized polyolefins, polycarbonate,polysulfones, polyimides, polyketones, liquid crystal polymers and anycombination thereof. It is contemplated that the durometer of catheterbody 12 may vary along its length.

At least distal region 14 of catheter body 12 is elastically deformable.That is, distal region 14 can be deformed into different shapes, butwill substantially return to its relaxed shape when the deforming forceis removed. Preferably, and as seen in FIGS. 1 and 2, the relaxed shapeof distal region 14 is a multi-loop spiral shape. That is, duringmanufacture (e.g., using a shaped mandrel or other suitable tooling),distal region 14 is predisposed to assume a multi-loop spiral shape whenno forces are applied thereto. In some embodiments of the invention, thevarious loops of the multi-loop spiral shape may have varying diameters.It is also desirable for the remainder of catheter body 12 to beflexible so that it can be navigated through a patient's vasculature toa location of interest as described below.

As used herein, the terms “spiral shape” and “multi-loop spiral shape”refer to a shape that spirals about and extends along a central axis. Inother words, the terms “spiral shape” and “multi-loop spiral shape” bothrefer to three-dimensional shapes.

Several variations on the multi-loop spiral shape of distal region 14are suitable for use in connection with the present invention. Forexample, the spiral shape may generally resemble a football, ahard-boiled egg, a barrel, a sphere, an ellipsoid, an oblate spheroid, aregular or irregular organic mushroom shape, conical shapes (e.g.,shapes that monotonically taper either towards or away from the distalend of distal region 14) or any other desirable shapes. One of ordinaryskill in the art will appreciate from this disclosure how to select asuitable spiral shape for a particular application of EP catheter 10.

The shape of distal region 14 defines both an inner surface (e.g., thatportion of the circumference of catheter body 12 that generally facesthe central axis of distal region 14) and an outer surface (e.g., thatportion of the circumference of catheter body 12 that generally facesaway from the central axis of distal region 14). A plurality ofelectrodes 16 are disposed on distal region 14, and, in some aspects ofthe invention, each of the plurality of electrodes 16 has anelectrically active region that is limited to the inner surface of thespiral shape as shown in the cutaway of EP catheter 10 illustrated inFIG. 3. Thus, when EP catheter 10 is introduced into a patient's heartchamber, the electrically active regions of electrodes 16 will not comeinto contact with cardiac tissue even if the outer surface of distalregion 14 does contact a cardiac surface. It is also desirable for thecentral axis of the spiral shape to extend continuously from thelongitudinal axis of the elongate catheter (e.g., for the straight,proximal portion of catheter body 12 to be generally centered on thespiral shape of distal region 14).

The electrically active regions of electrodes 16 may be defined byutilizing ring electrodes that are partially masked or insulated, forexample by covering the portions of electrodes 16 on the outer surfaceof the spiral shape with a dielectric material, polyester heat shrinktubing, or another suitable electrically insulating material.Alternatively, the electrodes may be sized such that they extend onlyabout the inner surface of the spiral shape (e.g., partial ringelectrodes), such that the entire surface of the electrode is theelectrically active region. Of course, a combination of masked/insulatedring, partial ring, or other types of electrodes (e.g., button- orspot-type electrodes) may be utilized without departing from the presentinvention. Combinations of electrode types can also be used eithersimultaneously or serially, as desired. In some embodiments of theinvention, distal region 14 may include up to sixty-four electrodes 16,though this embodiment is merely illustrative and more or fewerelectrodes may be utilized consistent with the present teachings.

In other embodiments of the invention, distal region 14 may also includeone or more additional electrodes 17 having electrically active regionsthat extend beyond the inner surface of the spiral shape. In certainaspects, electrodes 16 may alternate with electrodes 17 (e.g., everyother electrode on distal region 14 has an electrically active regiongenerally limited to the inner surface of the spiral shape). A suitableswitching mechanism may also be provided to permit manual or automatictoggling between a first operating condition where electrodes 16 areactive and a second operating condition where electrodes 17 are active.Such a configuration advantageously allows EP catheter 10 to be used inboth contact and non-contact electrophysiology studies and ablated viaelectrodes 17.

In still other embodiments, EP catheter 10 may be modified for use intherapeutic procedures in addition to electrophysiology studies. Forexample, EP catheter 10 may be used first to map cardiac activity andthen to ablate tissue to treat a detected arrhythmia. Thus, EP catheter10 may include a tip electrode 19 usable to deliver ablative energy toadjacent cardiac tissue. Tip electrode 19 may be between about 2 mm andabout 8 mm long. It is also contemplated that tip electrode 19 may beirrigated. Of course, alternative ablating elements (e.g., highintensity focused ultrasound (“HIFU”), laser, microwave, cryogenic, andthe like) may be utilized instead of tip electrode 19. It is alsocontemplated that electrodes 17 may be used to deliver ablative energy.

As generally known in the art, electrodes 16 and 19 may be used tomeasure electrophysiology data from the surface of the heart as part ofa cardiac mapping procedure or other electrophysiology study. Electrodes16 may also be utilized in conjunction with a localization system, suchas the EnSite NavX™ navigation and visualization system of St. JudeMedical, Atrial Fibrillation Division, Inc., to localize (that is, todetermine the position and/or orientation of) EP catheter 10 within apatient's body. Accordingly, each electrode 16 may be coupled to one ormore lead wires 17 (FIG. 6); these lead wires may be routed back to theproximal end of elongate catheter body 12 via a lumen 18 (FIGS. 3 and 6)extending therethrough. Alternatively, the lead wires may be embedded inthe wall of elongate catheter body 12. For example, U.S. applicationSer. No. 11/646,578, filed 28 Dec. 2006 and incorporated by reference asthough fully set forth herein, discloses a method of substantiallyembedding electrode lead wires in a catheter wall structure. Otherlocalization systems may also be used in connection with the presentinvention, including for example, the CARTO navigation and locationsystem of Biosense Webster, Inc., the AURORA® system of Northern DigitalInc., Sterotaxis' NIOBE® Magnetic Navigation System, or St. JudeMedical's MediGuide Medical Positioning System, all of which utilizemagnetic fields rather than electrical fields.

In some aspects of the invention, a shaping wire 20 (FIGS. 4 and 5) isutilized to predispose distal region 14 into the desired shape. Shapingwire 20 may optionally be a shape memory metal wire, for example a wirecomprising an alloy of nickel and titanium (known commercially as NiTior Nitinol), which helps distal region 14 of EP catheter 10 retain itsdesired shape. Alternatively, shaping wire 20 could be a strip ofstainless steel or another resilient metal in the nature of a springtemper wire or spring element. In still other embodiments, shaping wire20 could be a plastic material (e.g., a thermoset material or a shapememory plastic or polymer) or a combination of resin-based materials andshaping wires. FIGS. 4 and 5 illustrate one suitable shaping wire 20 inside and perspective views, respectively. Shaping wire 20 can be coupledto one or more anchor members (not shown), to electrodes 16, or to otherstructures within EP catheter 10.

It should also be understood that distal region 14 of EP catheter 10 mayinclude multiple shaping wires. One of ordinary skill in the art willappreciate how to utilize one or more shaping wires to predispose distalregion 14 into the desired spiral shape.

The term “shaping wire” is used herein to describe a strip of material(e.g., a circular or flat wire) that, after deformation, returns to itsformer shape. The term “shape memory wire” is used herein to refer to awire that has been deformed to a certain shape and briefly heated to fixthat shape. The wire possesses a memory causing it to return to itsfixed shape after being deformed. If the wire returns to its formershape without first being heated to a certain transition temperature, itmay be referred to as a “superelastic shape memory wire.” Bothsuperelastic and non-superelastic materials, however, are contemplatedfor use as shaping wire 20.

In some embodiments of the invention, such as the embodiment of theinvention illustrated in FIG. 6, shaping wire 20 will be embedded in thewall of catheter body 12 throughout distal region 14. Alternatively,shaping wire 20 may be encased in a polymeric tube 23 that is suitablybonded to catheter body 12 (e.g., to the inner wall of lumen 18), forexample as illustrated in FIG. 7. Of course, it is also within the scopeof the present invention for a first portion of shaping wire 20 to beencased in a polymeric tube and for a second portion of shaping wire 20to be embedded in the wall of catheter body 12.

In another aspect of the present invention, no shaping wire is used topredispose distal region 14 into the spiral shape. Instead, distalregion 14 is thermoset into the spiral shape.

Catheter body 12 may optionally include a working port 21 near distalregion 14. Working port 21 facilitates the introduction of additionaldevices, such as transducers and imaging devices, through catheter body12. In some embodiments of the invention, working port 21 passes apush/pull element (not shown), the end of which is coupled to the distalend of distal region 14 in order to “fine tune” the shape of distalregion 14 for a particular application. One of ordinary skill in the artwill recognize that, by pushing the push/pull element, the spiral shapeof distal region 14 will become longer and thinner (e.g., the radius ofthe spiral will tighten), as if the points of a football were pulledapart from each other. Conversely, by pulling the push/pull element, thespiral shape of distal region 14 will become shorter and wider (e.g.,the radius of the spiral will expand), as if the points of a footballwere pushed towards each other.

EP catheter 10 may be included as part of a kit for conducting cardiacelectrophysiology studies. In addition to EP catheter 10, such a kitgenerally includes an elongate tubular introducer 22, visible in FIGS. 1and 2, having a distal end 24, a proximal end (not shown), and a lumenextending from the distal end to the proximal end. Any suitableintroducer may be employed as part of a kit for conducting cardiacelectrophysiology studies provided it has an outer diameter sufficientlysmall to navigate the patient's vasculature (e.g., less than about 12French, and more preferably less than about 10 French) and an innerdiameter sufficiently large to accommodate EP catheter 10. In someembodiments, introducer 22 includes a steering mechanism (not shown)operable to deflect distal end 24 of introducer 22 in at least onedegree of freedom in order to facilitate navigating introducer 22through the patient's vasculature. For example, Patent CooperationTreaty application no. PCT/US08/54149, filed 15 Feb. 2008 and publishedon 21 Aug. 2008 as WO/2008/101206, discloses steerable introducercatheters that may be included in a kit according to certain embodimentsof the present invention. PCT/US08/54149 is hereby incorporated byreference as though fully set forth herein.

Catheter body 12 of EP catheter 10 can be inserted into the lumen ofintroducer 22. Because distal region 14 of catheter body 12 iselastically deformable, distal region 14 of catheter body 12 willsubstantially conform to the shape of introducer 22 when insertedtherein. This facilitates navigating introducer 22 and EP catheter 10through the patient's vasculature to a desired location. When distalregion 14 of catheter body 12 is extended distally from distal end 24 ofintroducer 22, however, it will resume the spiral shape as shown inFIGS. 1 and 2. To aid the practitioner in determining how far beyonddistal end 24 of introducer 22 catheter body is extended, the proximalend (e.g., the handle) of EP catheter 10 and/or introducer 22 mayinclude suitable indices. Alternatively, or in addition, fluoroscopicimaging or another suitable imaging modality may be employed tovisualize the deployment of EP catheter 10 from introducer 22.

In use, EP catheter 10 is introduced into a patient, for example intoone of a patient's heart chambers. It is desirable for EP catheter 10 tobe introduced into the patient in a substantially straightconfiguration, as this minimizes the size of the necessary incision andreduces the trauma to the patient. Typically, therefore, EP catheter 10is inserted into introducer 22, thereby causing distal region 14 ofcatheter body 12 to assume a collapsed shape substantially conforming tothat of introducer 22. The two devices can then be navigated through thepatient's vasculature until distal end 24 of introducer 22 is in thechamber of interest. With distal end 24 of introducer 22 in position,distal region 14 of EP catheter 10 can be deployed from distal end 24 ofintroducer 22, either by advancing EP catheter 10 distally or byretracting introducer 22 proximally. As distal region 14 of EP catheter10 emerges from introducer 22, it will return to the spiral shape intowhich it is predisposed.

With distal region 14 deployed in the chamber of interest,electrophysiological data can be gathered using electrodes 16, 17,and/or 19. As described above, this data can be gathered withoutbringing the electrically active regions of electrodes 16 into contactwith cardiac tissue. In some embodiments, a suitable controller may beemployed to allow a practitioner to disable electrodes 16, 17, and/or 19that are not advantageously positioned. Alternatively, a push/pullelement coupled to the distal end of catheter body 12 and passed throughworking port 21 may be used to elongate or compress distal region 14 inorder to “fine tune” the position of electrodes 16, 17, and/or 19.

Once the first heart chamber has been mapped, distal region 14 may bere-deployed into introducer 22, for example by retracting EP catheter 10proximally or by advancing introducer 22 distally. This will returndistal region 14 to the collapsed shape substantially conforming to theshape of introducer 22, which permits the two devices to once again benavigated through the patient's vasculature to a second of the patient'sheart chambers. With distal end 24 of introducer 22 in place in thesecond heart chamber, distal region 14 may once again be deployed out ofintroducer 22, where it resumes the spiral shape, in order to gatheradditional electrophysiological data. This process may be repeated manytimes, enabling EP catheter 10 to gather electrophysiological data atany number of locations of interest. Indeed, it is contemplated that EPcatheter 10 may also be introduced into certain locations of interestthrough a transeptal puncture. Of course, EP catheter 10 and/orintroducer 22 may be independently deflected to enhance intravascularand in-chamber navigation and placement of distal region 14.

Although several embodiments of this invention have been described abovewith a certain degree of particularity, those skilled in the art couldmake numerous alterations to the disclosed embodiments without departingfrom the spirit or scope of this invention. For example, though EPcatheter 10 and introducer 22 are described above as beingsimultaneously introduced into the patient's vasculature, alternativemethods of introducing EP catheter 10 into the patient are contemplated.For example, introducer 22 may be navigated to the desired locationfirst (e.g., introduced over a guidewire or using a stylet), and then EPcatheter 10 may be inserted into introducer 22. As another example, EPcatheter 10 may be introduced into the patient without the use ofintroducer 22, such as by using a stylet or other straightening deviceto place distal portion 14 into the collapsed configuration.

All directional references (e.g., upper, lower, upward, downward, left,right, leftward, rightward, top, bottom, above, below, vertical,horizontal, clockwise, and counterclockwise) are only used foridentification purposes to aid the reader's understanding of the presentinvention, and do not create limitations, particularly as to theposition, orientation, or use of the invention. Joinder references(e.g., attached, coupled, connected, and the like) are to be construedbroadly and may include intermediate members between a connection ofelements and relative movement between elements. As such, joinderreferences do not necessarily infer that two elements are directlyconnected and in fixed relation to each other.

It is intended that all matter contained in the above description orshown in the accompanying drawings shall be interpreted as illustrativeonly and not limiting. Changes in detail or structure may be madewithout departing from the spirit of the invention as defined in theappended claims.

What is claimed is:
 1. An electrophysiology catheter, comprising: anelongate catheter body comprising an elastically-deformable distalregion including a portion predisposed to assume a spiral shapecomprising an inner surface on an inside of the spiral shape configurednot to contact tissue and an outer surface on an outside of the spiralshape capable of contacting tissue when in a relaxed condition, thedistal region terminating in a distal tip; and a plurality of electrodesdisposed on the distal region, each of the plurality of electrodescomprising an electrically active region, wherein there are noelectrically active regions on the outer surface of the spiral shapedportion of the distal region.
 2. The electrophysiology catheteraccording to claim 1, further comprising a shape memory materialextending through the distal region of the catheter body to predisposethe spiral shaped portion of the distal region into the spiral shape. 3.The electrophysiology catheter according to claim 2, wherein the shapememory material comprises a shape memory metal wire.
 4. Theelectrophysiology catheter according to claim 3, further comprising apolymeric tube, and wherein at least a portion of the shape memory metalwire is encased in the polymeric tube.
 5. The electrophysiology catheteraccording to claim 2, wherein the shape memory material comprises ashape memory polymer.
 6. The electrophysiology catheter according toclaim 1, further comprising a spring element extending through thedistal region of the catheter body to predispose the spiral shapedportion of the distal region into the spiral shape.
 7. Theelectrophysiology catheter according to claim 1, wherein the distalregion of the catheter body comprises a polymeric material thermosetinto the spiral shape.
 8. The electrophysiology catheter according toclaim 1, wherein at least some of the plurality of electrodes comprisering electrodes, wherein portions of the ring electrodes on the outersurface of the spiral shape are covered by an electrically insulatingmaterial.
 9. The electrophysiology catheter according to claim 1,wherein at least some of the plurality of electrodes extend about afraction of the inner surface of the spiral shape.
 10. Theelectrophysiology catheter according to claim 1, wherein the spiralshape has a central axis, the elongate catheter has a longitudinal axis,and the central axis of the spiral shape extends continuously from thelongitudinal axis of the elongate catheter.
 11. A kit for conductingelectrophysiology studies, comprising: at least one of a guidewire and atubular introducer comprising an elongate introducer body comprising adistal end, a proximal end, and a lumen extending from the proximal endto the distal end; and an electrophysiology catheter comprising anelongate catheter body adapted to be one of deployed through the lumenof the introducer or introduced over the guidewire and comprising anelastically-deformable distal region predisposed to assume a spiralshape having an inner surface on an inside of the spiral shapeconfigured not to contact tissue and an outer surface on an outside ofthe spiral shape capable of contacting tissue when the distal region ofthe elongate catheter body is in a relaxed state unconstrained by theintroducer body or guidewire; a plurality of electrically active regionson the distal region of the elongate catheter body, wherein each of theplurality of electrically active regions is limited to the inner,non-tissue-contacting surface of the spiral shape; and wherein there areno electrically active regions on the outer surface of the spiral shape.12. The kit according to claim 11, wherein at least some of theplurality of electrically active regions comprise ring electrodes havingan electrically insulating material covering portions of the ringelectrodes on the outer surface of the spiral shape.
 13. The kitaccording to claim 11, wherein the tubular introducer includes asteering mechanism operable to deflect the distal end of the elongateintroducer body in at least one degree of freedom.
 14. Theelectrophysiology catheter according to claim 1, wherein the distal tipincludes a tip electrode.
 15. The electrophysiology catheter accordingto claim 1, wherein the spiral shaped portion of the distal regionincludes at least two turns about and extending along a central axis.16. An electrophysiology catheter, comprising: an elongate catheter bodycomprising an elastically-deformable distal region predisposed to assumea three-dimensional shape surrounding and extending along a central axiswhen in a relaxed condition, the distal region having an inner surfaceon an inside of the three-dimensional shape that faces the central axisand is configured not to contact tissue and an outer surface on anoutside of the three-dimensional shape capable of contacting tissue; anda plurality of electrodes disposed on the distal region, each of theplurality of electrodes comprising an electrically active region,wherein the outer surface of the distal region is devoid of electricallyactive regions.
 17. The electrophysiology catheter according to claim16, wherein the three-dimensional shape comprises a spiral shape. 18.The electrophysiology catheter according to claim 16, wherein theelongate catheter body terminates in a distal tip comprising a tipelectrode.
 19. The electrophysiology catheter according to claim 16,wherein the entirety of the outer surface of the three-dimensional shapeis devoid of electrically active regions.